Conventionally, an apparatus employing a disc-shaped recording medium, such as an optical disc, is provided with a loading mechanism for loading a disc, as an information recording medium, on a reproducing unit or on a recording unit within the main body unit of the apparatus. For the loading mechanism, provided to the recording and/or reproducing apparatus, a tray system and a slot-in system are used.
The loading mechanism of the tray system loads a disc thereon using a tray movable across the inner and outer sides of the main body unit of the apparatus. In this loading mechanism, a disc is set on a tray pulled out to a loading/unloading position outside the main body unit of the apparatus, and pulls the tray into the inside of the main body unit of the apparatus, such that the disc set on the tray is moved onto a reproducing unit or a recording unit to effect disc loading.
The loading mechanism of the tray system is in need of two-stage operations, namely an operation of causing movement of the tray, carrying the disc, across the inner and outer sides of the main body unit of the apparatus, and an operation of causing movement of the disc on the tray in a direction perpendicular to the direction of tray movement to chuck the disc on a rotational driving mechanism of the reproducing unit or the recording unit.
On the other hand, the loading mechanism of the slot-in system only needs to introduce the disc via a disc insertion opening provided in the main body unit of the apparatus, the disc being then transported to the reproducing unit or the recording unit by a transport mechanism provided in the main body unit of the apparatus so as to be then chucked on the rotational driving mechanism of the reproducing unit or the recording unit. With the loading mechanism of the slot-in system, in which there is no necessity of employing a tray, the recording and/or reproducing apparatus itself can be reduced in thickness, while only a small amount of operations is required for loading the disc, thus assuring facilitated disc loading operations.
As for the recording and/or reproducing apparatus, employing a disc-shaped recording medium, such as an optical disc, as a recording medium, such a recording and/or reproducing apparatus has been proposed which is provided with a disc exchanging function such that a plural number of discs are housed in a housing section at the outset and a desired one of the discs is selected for recording and/or reproducing information signals. The recording and/or reproducing apparatus provided with this sort of the disc exchanging function may be exemplified by an apparatus disclosed in the Japanese Laying-Open Patent Publication H-11-203761.
The recording and/or reproducing apparatus, disclosed in this Publication, includes a housing section in which can be accommodated a plural number of Compact Discs as optical discs with a diameter of 12 cm. This recording and/or reproducing apparatus includes a transport mechanism which is able to transport the discs, introduced into the main body unit of the apparatus via a slot provided therein, to the reproducing unit. The recording and/or reproducing apparatus also includes a mechanism for transferring the discs not in use to a standby position in the housing section in the main body unit of the apparatus. The mechanism for transferring the discs to the housing section in the main body unit of the apparatus includes the function of transferring the discs housed in the housing section to the reproducing section for loading thereon subject to selection by a user.
Meanwhile, as a disc-shaped recording medium, for example, an optical disc, in particular a Compact Disc, a disc with a diameter of 12 cm and a disc with a diameter of 8 cm, is used. If the disc with different diameters are used on the same recording and/or reproducing apparatus, and the disc transport device is of, for example, the slot-in type, the following problems, namely    (1) difficulties in positioning the discs in the standby position ready for chucking the disc to the reproducing unit;    (2) difficulties in loading the discs between the reproducing unit and the loading unit; and    (3) difficulties in arraying the discs in accommodating the discs in the disc housing unit are encountered.
First, in (1), that is in positioning the disc in a standby position ready for chucking the discs in a reproducing unit, there is presented no problem in the case of an apparatus not having a disc exchanging function, that is in a recording and/or reproducing apparatus in which only one disc is housed and loaded on a recording unit or a reproducing unit for recording or reproducing information signals.
In (2), there is similarly presented no problem in connection with disc transport. However, in case (1) and (2) above are added together, difficulties become outstanding, such that it becomes difficult to overcome the both of the problems simultaneously. For example, in order to handle two disc sorts of different diameters, there are required a mechanism for transferring the respective discs from an insertion opening to the reproducing unit and a mechanism for transferring the disc from the disc housing position in the apparatus to the reproducing unit, thus complicating the mechanism for holding and positioning the two discs of different sorts.
In (3), the arraying difficulties presented are associated with the difficulties met in providing a mechanism for arraying a disc with a diameter of 12 cm and a disc with a diameter of 8 cm within a housing section for the two discs of different diameters.
For overcoming these difficulties, complicated mechanical designing is required, as a result of which the number of components and the cost are necessarily increased.
In using a disc with a diameter of 8 cm, an adapter for changing the diameter to 12 cm may be used for compatibility with the disc 12 cm in diameter. In this case, it is sufficient to provide a housing section or a transporting mechanism for a disc 12 cm in diameter. However, if such adapter is used for effectively changing the outside diameter of the disc, difficulties are presented in positively mounting the disc to the adapter. Moreover, the operation is complicated because the user has to load the disc to the adapter. In addition, means must be provided to prevent an inconvenience when a disc 8 cm in diameter is introduced inadvertently via insertion opening without being loaded on the adapter.